Suggestions for PVE (assuming new areas are still being created?)
I would like to suggest some interesting game mechanics that I have experienced playing MMO’s for the last 8 years that may work for CF.

1) Rather than the usual kill mob 1, then kill mob 2, then mobs 3 etc. You could have 2 boss mobs where you have to kill both mobs within say 2 or 3 rounds of combat of each other. Otherwise one mob restores the other mob back to full health. To make this annoyingly fun you have one mob hit much harder and have less hp than the other.

2) Periodic reflect, so every so often in the fight the boss gets a reflect buff where instead of taking damage, you take that damage. In practise this could work where the mob takes normal damage from physical hits, then when he gets the reflect buff, you need to switch to magical weapon, to prevent just using a magical weapon he would be very resistant to anything he can’t reflect.

3) Add pulling. For example you fight a strong boss with lots of hp in a room and you need to pull a lever which sends in more mobs you have to kill same time. If you kill a specific number of adds you get a better reward when the boss dies. The lever stops working if you kill boss and the boss gets a damage buff for every add.

4) NPC versus boss. Once you walk in, the fight is on, weak goodie versus tough evil. If the goodie dies you miss out on reward (he unlocks chest or something afterwards but cant if dead). So you have to find a balance between healing the goodie or rescuing and killing the evil boss, who likes to switch back to the NPC occasionally.

5) Absorbing boss, boss mob is immune to everything unless you kill an add, adds can be in different rooms, each time you kill an add you get you certain amount of time to hurt boss. The timer might need to be variable to number of people in the area to be fair. This does not need to be an add, someone in your party can do something else to activate.